This paper reports the relationship between residual stress distribution and key friction stir welding parameters, transverse and rotational speeds, on 6056-T4 aeronautical aluminium alloy. Standard electric strain gauge based destructive technique was used to measure residual stresses at the top of the weld in the longitudinal direction. Residual stresses across the weld had the “M” distribution with asymmetry across the advancing and retreating sides. Location of retreating side tensile residual stress maximum was the weakest zone and microhardness minimum across the weld. Tensile longitudinal residual stress minimum and maximum at the retreating side of the weld reduced with increased translational speed and advance per revolution.